La Marzocco GB5/FB80 steam valve knob/stem retro-fit kit for serial #4999 and lower. Fast shipping when in stock. When out of stock this becomes a special order item and typically requires 2-4 weeks for processing prior to shipping. Specifications: Full retrofit kit (multiple components listed) Compatibility: La Marzocco GB5 and FB80 (serial #4999 & lower) Installation: Valve stem/knob retrofit Recommended for qualified technician. Pro tip: Additional knob cover, stopping screw, and fixing nut may be needed.